Method for pre-doping negative electrode active material and method for manufacturing electrode for electric device and electric device

Abstract

There is provided a means capable of suppressing generation of a lithium dendrite at the time of charging and discharging while sufficiently suppressing an amount of gas generated at the time of initial charging of an electric device. When a lithium ion is doped in advance to a negative electrode active material, which is used in an electric device including a positive electrode and a negative electrode, after performing a pre-doping step of doping the lithium ion to a negative electrode active material to be doped to reduce a potential (vs. Li+/Li) of the negative electrode active material to be doped with respect to a lithium metal, a dedoping step of dedoping the lithium ion from the negative electrode active material doped with the lithium ion in the pre-doping step to increase a potential (vs. Li+/Li) of the negative electrode active material with respect to the lithium metal is performed.

1 .- 9 . (canceled) 
     
     
         10 . A method for pre-doping a negative electrode active material, the method doping a lithium ion in advance to a negative electrode active material, which is used in an electric device including a positive electrode and a negative electrode, the method comprising:
 a pre-doping step of doping the lithium ion to a negative electrode active material to be doped to reduce a potential (vs. Li+/Li) of the negative electrode active material to be doped with respect to a lithium metal; and   a dedoping step of dedoping the lithium ion from the negative electrode active material doped with the lithium ion in the pre-doping step after the pre-doping step to increase a potential (vs. Li+/Li) of the negative electrode active material with respect to the lithium metal, wherein   the negative electrode active material doped with the lithium ion in the pre-doping step is mixed with a negative electrode active material having a potential nobler than that of the negative electrode active material doped with the lithium ion, in the dedoping step, so that the dedoping step is performed with respect to the negative electrode active material doped with the lithium ion.   
     
     
         11 . The method for pre-doping an active material according to  claim 10 , wherein, when a potential of the negative electrode active material with respect to the lithium metal at an end of the pre-doping step is designated as a first potential (E 1 ) and a potential at which a gas generation amount when the lithium ion is firstly doped to the negative electrode active material to be doped becomes maximum is designated as E g (max), the first potential (E 1 ) satisfies E 1 ≤E g(max) . 
     
     
         12 . The method for pre-doping an active material according to  claim 10 , wherein, when a potential of the negative electrode active material with respect to the lithium metal at an end of the dedoping step is designated as a second potential (E 2 ), the second potential (E 2 ) is a potential at which an initial discharge capacity of the electric device becomes maximum. 
     
     
         13 . The method for pre-doping an active material according to  claim 10 , wherein the material having a potential nobler than that of the negative electrode active material doped with the lithium ion is a same negative electrode active material as the negative electrode active material doped with the lithium ion and is a negative electrode active material having a shallower dope depth than that of the negative electrode active material doped with the lithium ion. 
     
     
         14 . The method for pre-doping an active material according to  claim 10 , wherein the active material to be doped is hard carbon. 
     
     
         15 . A method for manufacturing a negative electrode for an electric device, the negative electrode being used in an electric device including a positive electrode and a negative electrode, the method comprising:
 pre-doping the active material to be doped by the method for pre-doping a negative electrode active material according to  claim 10  to obtain a negative electrode active material doped with a lithium ion and then manufacturing the negative electrode by using the negative electrode active material doped with the lithium ion.   
     
     
         16 . A method for manufacturing an electric device including a positive electrode and a negative electrode, the method comprising:
 obtaining a negative electrode for an electric device by the method for manufacturing a negative electrode for an electric device according to  claim 15  and then manufacturing the electric device by using the negative electrode for an electric device.   
     
     
         17 . The method for manufacturing an electric device according to  claim 16 , wherein the electric device is a lithium ion secondary battery or a lithium ion capacitor.